1. Technical Field of the Invention
The invention relates generally to preparing metal units, such as metal plates, so that they will be properly spaced when stacked. More specifically, the invention relates to preparing copper cathodes so that they may be stacked for better/optimal melting, or for better/optimal chemical reactions.
2. Problem Statement
Metal plates (also called sheets) are commonly used in industrial applications. For example, some copper metal sheets may be used as copper cathodes in mining operations. In addition, zinc metal sheets are used as anodes in industrial water applications to prevent the xe2x80x9cpittingxe2x80x9d of a metallic container.
Accordingly, in the mining industry, the copper cathodes are used in copper bearing solutions of sulfuric acid and water. More specifically, a copper leaching process called SXEW (solvent extraction/electrowinning) is used at most copper mines to extract copper from oxide ores. In practice, this process (called leaching) runs acid and water through a pile or dump of copper bearing oxide ore, and collects the resulting solution for further processing. Accordingly, copper mining and many other industrial processes utilize a large number of metal plates.
Sometimes, due to size limitations, space needed in an industrial application, melting qualities, or other factors, a metallic rod is preferable to a metal plate. Accordingly, sometimes the word xe2x80x9cmetal unitxe2x80x9d is used to describe a metal plate (metal sheet), metal rod, or any other type of stackable metallic processing pieces.
Bundling is the process of gathering and stacking metal units for transport or storage (thus creating a xe2x80x9cbundlexe2x80x9d of metal units). Although bundling may be interpreted by some to imply the application of a securing device to a bundle, as used herein, bundling means the association of two or more metal units, regardless of purpose. Typically, although not necessarily, the association is a stacking of the metal units.
Unfortunately, many metal units are destroyed or lost in transport between a manufacturing or storing site, and an industrial location that utilizes the metal units. This is because securing devices, such as metal bands, that are used to support metal units in transport are often insufficiently strong to withstand the forces and momentum generated by otherwise apparently static metal units. Accordingly, shearing and other forces often cause metal bands to break, or may cause a stack of metal units to fall over. Accordingly, many metal units fall off trucks, trains, or other transport vehicles. Furthermore, stacks of metal units may fall, or slide in a one-on-top-of-each-other fashion, and damage facilities or equipment. Therefore, it would be advantageous to have methods for bundling metal units that more securely maintain the metal units in a stack or other position.
Sometimes, when stacking metal units, the weight of the metal unit itself will cause the center portion of the metal unit to sag. Occasionally, the sagging will be severe enough to cause one metal unit to touch another metal unit. This sagging may result in unpredictable spacing between metal units. Because the spacing between metal units is unpredictable, physical and chemical properties of the reactions involving the metal units are not predictable. For example, unpredictable spacing of metal units makes it difficult to predict heat dissipation, and therefore, the melting properties of the metal units are also unpredictable. In addition, the unpredictable spacing of metal units creates uncertainty in chemical flow between metal units that are undergoing a chemical reaction. Therefore, for these and other reasons it would be advantageous to have methods for spacing metal units in a stack or other position.
The invention provides technical advantages as methods and devices that enable the spacing of metal units. In one embodiment, the invention is a method of modifying a metal unit to enable spacing. The method generally identifies a dimple location on the metal unit, and applies a force at the dimple location to create a spacing feature.
The method may also include selecting a spacing feature typexe2x80x94such as a dimple, a bubble, a rib, or an impression. In addition, the plurality of dimples may be used. For example, three dimples spaced approximately at the corners of an equilateral triangle, or four dimples spaced approximately at the corners of a square, may be centered about the midpoint of a metal unit to provide for predictable and reliable spacing. The metal unit may be a metal plate, such as a copper cathode, or zinc anode.
In another embodiment, the invention is a nestable and spacable metal sheet. The metal sheet is preferably a copper cathode. Furthermore, the metal sheet may have nesting features such as a generally polygonal impression.
In yet another embodiment, the invention is a nestable copper cathode for use in sulfuric acid bearing solutions, comprising a nesting feature and a spacing feature, the spacing feature comprising at least one dimple. Of course, other features and embodiments of the invention will readily apparent to those of ordinary skill in the art, and thus, similar results as described herein can be achieved in not dissimilar manners. Accordingly, the following discussion should not be read as limiting, and the scope of the invention should be read as limited only as defined in the CLAIMS.